Implantable fastening devices for reconstructing the anterior cruciate ligament (ALC) or the posterior cruciate ligament (PCL) make use of a graft that is made to measure. The graft is generally made using the “internal rectus” (RI) tendon or “gracilis” tendon, and the semi tendonius (ST) tendon. The operating technique associated with preparing this graft may be referred to as the “IRST” technique.
The operating technique that consists in using only the semi tendonius tendon folded in four may be referred to as the “ST4” technique.
The operating technique using the central portion of the ligamental patellae is referred to as the “Kenneth Jones” or “KJ” technique for the surgeon who developed it.
All of those surgical treatment methods comprise placing a graft constituted by one or more tendons under arthroscopic monitoring in a tunnel in bone made by drilling into the head of the femur or of the tibia.
The “internal rectus” and the “semi tendonius” muscles are two similar muscles, which together with a third muscle, namely the “sartorius” muscle, form the “pes anserinus”. They are also referred to as the “hamstring” muscles and they are located on the medial portion of the thigh. The tendons at this position of the thigh are very long and they are attached to the medial face of the tibia after crossing the knee. It is possible to take these tendons via a small incision of a few centimeters using an instrument of the “stripper” type, which detaches them over their entire length.
Once the tendons have been taken, they are joined together and folded in half, thereby making it possible to form a new ligament referred to as a graft or an autograft that comprises four strands having traction strength that is thus greater than that of a normal anterior cruciate ligament (ACL).
The tunnels drilled in the femur and the tibia enable the graft to be passed inside the joint so as to place it at the location where the anterior cruciate ligament used to be situated. The tunnels in the femur and the tibia open out at the location for the natural attachments of the ligaments. The positioning of these tunnels in the tibia and the femur is important since it has an influence on the subsequent postoperative stability of the knee. The tunnel in the femur is made directly inside the joint via one of the two orifices of the arthroscope or via the previously-drilled tunnel in the tibia. The tunnel in the femur may also be drilled by using a small incision made in the lateral face of the thigh.
The graft is fastened using medical devices at the ends of the previously-drilled tunnels in the femur and the tibia.
Implantable fastening devices are known that are used in particular in the IRST and ST4 operating techniques, which devices comprise fastening means for fastening the ends of the graft to the joint, said fastening means for example being an interference screw inserted in the wall of the tunnel containing the graft and thus blocking the graft against the wall of the tunnel.
The graft may also be fastened by fastening a textile strip to one or both ends of the graft, the fastening means then being applied directly to the textile strip and not to the graft. Another fastening technique comprises a cage arranged in a tunnel and having an inside bore suitable for co-operating with the screw pitch of a blocking screw, the textile strip being blocked in the cage by the screwed-in blocking screw.
Devices of that type do not enable the position of the graft to be adjusted in the tunnels in the femur and the tibia after it has been put into place without new surgery.
WO 2012/154922 provides an implantable device having a hollow elongate element with at least a portion thereof being passed through two through openings of a bearing button, a first end of the elongate element is passed inside the elongate element in its second end and then leaves over the length thereof so as to form a clamping loop. In operation, the size of the clamping loop is adjusted by exerting traction on the free first end of the elongate element, which first end extends at least in the femoral canal and thus comes into contact with the graft. There is thus a risk of abrading and thereby damaging the graft and of modifying its position in the femoral canal, and possibly also in the tibial canal if the first end also extends in that canal.
FR 2 980 356 provides a device having an elongate element provided in two zones of its length with at least two grommets, each receiving one end of the elongate element so as to form two clamping loops. A portion of the elongate element is passed through two through openings of a bearing button.
In comparison with WO 2012/154922, the two free ends of FR 2 980 356 extend away from the two clamping loops, thereby avoiding the two free ends extending through the femoral canal, and possibly the tibial canal.
Nevertheless, traction exerted on the free ends of the elongate element can only adjust the size of the loops in connection with the graft. The device is not provided with means for locking the graft in its implantation position, since if tension is exerted on the graft through the femoral canal, and possibly through the tibial canal, the strands of the elongate element arranged in the loops slide, with the clamping loops becoming larger and the graft is no longer correctly tensioned, and is moved away from its implantation position.
There thus exists a need for an implantable fastening device for fastening a graft to at least one bone of a joint and that enables the position of the graft to be adjusted in at least one bone canal, in particular the femoral canal and the tibial canal, enabling the graft to be locked in said bone canal, in particular the femoral canal and the tibial canal, in a manner that is removable without new surgery; and means for adjusting the position and the tensioning of the graft, with this being done in removable manner.
There also exists a need for an implantable fastening device that is simple to use and that limits the amount of friction exerted on the graft in order to preserve its mechanical properties.